SECTION 7 - The HIU Controller first power up and set up
SECTION 11 - Fault and Error Codes / Fault finding guide
code
Cause
Effect
Remedy
E1
The measured primary temperature is lower
than the set point temperature is for heating
so the HIU will not be able to achieve the set
temperature. This is after approximately 60
seconds of flow.
The function is re-enabled when the primary
exceeds the setpoint temperature.
Check the set point in the controller, adjust if the
set point is set higher than the design supply
temperature.
Check that the primary temperature probe is
correctly connected to the primary pipe.
When the primary temperature and set point are
aligned, the error code E1 automatically
disappears.
E2
In installations where Radiators are at very
high temperatures, then this is a warning
that the return temperature is higher than
the maximum allowed in parameter 20.
As this is a safety function, the PICV closes until the
sensor on the primary return sees a temperature
drop of 10C below the parameter 20 set point for
maximum.
Check parameter 20 is set correctly, if too low,
reset this at 5C higher than secondary heating
flow set temperature. Check the temperature
probe is positioned correctly. Reset (turn power
on and off) to recalibrate the PICV actuator.
E3
The controller is recognising and warning
that the HIU performance is not as the
algorithm predicts. The energy transfer is
poor, and the HIU is not delivering heat as it
should be.
Heat transfer is inefficient, heating capacity
reduced and temperature control unstable.
If signs of blockage it could be the strainer is
blocked or the PHE is partially blocked with lime
scale. Check PICV fully open and check flow on
the heat meter. Low flow value would prove that
a blockage of some sort is the issue.
E5
Heating is not reaching the set point so is
performing poorly or not at all.
Heating stops after 20 minutes and shows the E5
code.
Resets after 30 seconds
Or Error LEDs on the pump?
Power ON and OFF at the mains switch, this
allows the PICV to recalibrate, and in doing this will
allow a small flow into the PHE, which then proves
the PICV and Diverter not at fault.
Check the following possibilities.
- Primary temperature is too low?
- Is the set temperature on the controller higher
than the incoming primary (network)
temperature and temperature is impossible to
reach? Rest set the temperature so it is 10C lower
than the primary.
- PICV blocked / strainer blocked?
- Diverter in the wrong posion?
E6
Temperature information from the heating
temperature sensors is wrong or unusual.
Return temperature is too high with no apparent
control being seen.
This error code is showing that either;
1.The heating temperature sensors have been
wrongly positioned with the flow on the return
and the return on the flow, change them to their
correct position.
2.The installer has not connected the primary
connections correctly, with the flow connected to
the return connection. Check temperatures.
E7
The heating return temperature is too high
and the HIU is warning the operator. Various
causes may be considered, example all TRVs
may be closed with only 1 x small radiator
open, but the room thermostat is still calling
for heat.
Various causes may be considered, example all
TRVs may be closed with only 1 x small radiator
open, but the room thermostat is still calling for
heat. The return temperature is much too high, so
the HIU ceases .The effect is that the controller
shuts down the pump before re-starting again after
10 minutes.
The E7 will automatically reset itself aſt er 10
minutes. Attention should be paid to the set up of
the heating radiators and controls.
Is the room thermostat positioned correctly to
turn off before all the TRVs shut down?
Is the radiator circuit balanced correctly at the
radiator valves? E7 may occur under certain test
conditions where unnatural operating conditions
are forced.
E8
The PICV actuator cable has
been disconnected from the controller or
there’s a failure on the actuator itself.
The E8 code appears on the screen.
Heating is no longer available.
To avoid over heating risk , when the HIU detects a
heating flow temperature 10°C above setpoint for
more than the programmed time interval
(90 seconds factory set, adjustable up to 210
seconds) the HIU will shut down and show an E8
error code. Pump will switch off.
Allow the unit to cool down first! Check PICV
actuator connection, and that the valve stem pin
is not jammed (free if possible).
Power OFF then ON again, check for movement
in the actuator stem. Replace the actuator if
found to be seized. Replace the valve cartridge if
found to be seized.
Diagnostics - Error code definitions.
When an error code is displayed, the controller is warning of unsuitable operating conditions that may be causing the HIU to operate inefficiently or
possibly, not at all. If left in that state, these conditions could become a safety issue.
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